This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-225689, filed Jul. 26, 2001 the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a method and device of forming a coating film in a manufacturing process of a semiconductor device and a method of manufacturing a semiconductor device using the above-mentioned method.
2. Description of the Related Art
The photolithography step of a manufacturing process of a semiconductor device, a liquid crystal device, etc., constitutes an important step of forming various interconnect patterns. This photolithography step is the technique of, for example, transferring an interconnect pattern by an exposure device called a stepper to a photoresist, after the photoresist has been coated on a semiconductor substrate, and forming a photoresist pattern by developing the coated photoresist with an aqueous alkali solution. As a liquid material coating film for use in a semiconductor device etc., there are not only the resist coating film but also an anti-reflection film, a mask film (SOG film), an insulating interlayer (SOD film), a low dielectric constant film (Lok film) and so on. The method and device of forming these films constitute a coating film forming method and device.
In a resist coating process using a conventional photoresist coating device as shown in FIG. 9, a semiconductor wafer 101, such as silicon, serving as a substrate to be processed is set on a spin chuck 102 which vacuum sucks the semiconductor wafer 101 and which is rotatable at high speeds. A photoresist supply nozzle 105 is so provided at an arm 103 so as to be set opposite to the semiconductor wafer 101 above the spin chuck 102. A photoresist is supplied from the photoresist supply nozzle 105 onto the semiconductor wafer 101. After this, the spin chuck 102 is rotated to allow the photoresist on the semiconductor wafer 101 to be spin-dried. A solvent supply nozzle 106 is mounted on the upper end of a movable arm 104 at an outer peripheral side of the spin chuck 102. After the photoresist has been spin-dried, the solvent supply nozzle 106 supplies a solvent onto the photoresist at the outer peripheral portion of the semiconductor wafer 101 while the semiconductor wafer 101 is rotated. By doing so, only the photoresist on the outer peripheral portion of the semiconductor wafer 101 is dissolved and removed.
If the drying of the photoresist is not adequate, the coating film and solvent are mixed together, thus causing a bulge at the outer peripheral edge portion of the coating film. As shown in FIG. 8B, therefore, the thickness of the photoresist film at the outer peripheral portion of the semiconductor wafer 101 becomes thicker. This causes the coating film to be left there at a time of etching. It is, therefore, necessary to make the etching time longer so as to eliminate such a thicker portion. As a result, the throughput is lowered. Further, in the conventional technique, the solvent in the photoresist is volatilized through the rotation action to attain the drying of the photoresist and it is, therefore, necessary to rotate the semiconductor substrate for a longer time so as to attain the adequate drying of the coating film. This process also leads to a lowering of the throughput. Further, at the time of spin-drying the semiconductor wafer, the rotation is slower at the central portion, so that the drying extent becomes slower than at the peripheral portion of the semiconductor wafer. With a tendency toward an increase of a wafer size from 8-inch to 12 inch, the extent of drying greatly differs depending upon the positions of the semiconductor wafer (that is, the extent of drying is slower at the central portion and faster at the peripheral portion of the semiconductor wafer). For the conventional technique, therefore, it becomes difficult to take a corresponding countermeasure.
According to a first aspect of the present invention, there is provided a method of forming a film comprising coating a liquid material on a surface of a substrate to form a material film of the liquid material the on the surface of the substrate, while rotating the substrate; and drying the material film, while rotating the substrate and letting air or nitrogen gas blow onto a predetermined area of the material film.
According to a second aspect of the present invention, there is provided a method of forming a semiconductor device comprising coating a liquid material on a surface of a substrate to form a material film of the liquid material on the surface of the substrate, while rotating the substrate; drying the material film under the rotation of the substrate while letting air or nitrogen gas blow onto a predetermined area of the material film; coating a resist on a surface of the material film to form a resist film on the surface of the material film, while rotating the substrate; drying the resist film under the rotation of the substrate while letting air or nitrogen gas blow onto a predetermined area of the resist film; patterning the resist film to form a resist pattern; and patterning the material film to form a material pattern of a predetermined shape using the resist pattern as a mask.
According to a third aspect of the present invention, there is provided a film forming device comprising a supporting table configured to support a substrate; and a gas blowing nozzle provided in opposition to the substrate and configured to let a gas including air or nitrogen gas blow onto the substrate.